Video conferencing is interactive two-way visual and audio communication between two or more parties who are geographically separated.
FIG. 1 shows a conventional conferencing system set-up. For simplicity, FIG. 1 shows the conferencing system set-up distributed at two sites, A and B. The two sites are connected through a transmission channel 1300 and each site has a loudspeaker 5A and 5B, respectively, and a microphone 4A and 4B, respectively. The arrows in FIG. 1 indicate the direction of propagation for an acoustic signal, usually from the microphone to the loudspeaker.
FIG. 2 illustrates a typical video conferencing room 1, with a video conferencing system 2. Video conferencing systems 2 usually consist of the following components; a codec 10 (for coding and decoding audio and video information) comprising an internal loudspeaker (not shown), a user input device 8 (i.e. remote control or keyboard), a video capture device 6 (camera), an audio capture device 4 (microphone), a video display 9 (screen) and an audio reproduction device 5 (loudspeakers). However, not all systems are alike, and the integration level of these components can vary greatly between different models.
The level of integration span from fully integrated systems where all of these components are combined into one unit, to so-called set-top systems, where a box containing only a camera 6 and codec 10 can be placed on top of any television set. A television set usually contains both speakers 5 and a screen 9, which is then used to play audio and display video from the codec 10 in the set-top system. In the latter case, the audio playback device 5 is usually controlled by the channel selection, and is therefore always playing back the audio signal associated with the selected channel or video signal.
Newer plasma and LCD screens are thinner than traditional CRT television sets, with little or no space for set-top systems. The codec 10 must therefore be placed elsewhere, but cameras 6 are still typically placed on top of the combined audio and video playback device.
Industrial espionage is an increasing problem in many countries, and the rapid pace of technology is making espionage, such as eavesdropping, ever more of a potential problem for companies today. Confidential information and/or prototypes are desirable objects both to business competitors, and to employees seeking to strike out on their own with the company's hard work, trade secrets and other intellectual property as their personal start-up capital. Confidential information are usually acquired by people who are on the payroll and are bribed, or people who gain employment, or are placed on the payroll by a competitor, for the express purpose of acquiring sensitive data.
Videoconferencing systems 2 are typically placed in meeting rooms 1 where sometimes confidential information is discussed or prototypes are exhibited. Due to the fact that the codec 10 is not controlling the television/monitor, it cannot reliably verify that the television/monitor is actually turned on, or has the right input or channel selected to play back audio (and display video) coming from the codec 10. Therefore, people in this meeting room 1 might not realize that the video conferencing equipment 1 might be in a call and transmit sensitive audio and video to a remote user. Consequently, an unauthorized far end party can listen in on a meeting, without the near end party detecting this eavesdropping. This is a serious security problem.
Video conferencing systems 2 with separate video/audio systems (television sets, projectors etc.), or fully integrated systems where the screens can be turned off, has shown to constitute a security risk. Modern video conferencing systems 2 are typically configured to “auto-answer”, meaning that the system automatically accepts any incoming call. If, in such cases, the television/monitor is switched off or displaying images from another source (DVD, cable TV, computer etc.), and a remote user dials in to the meeting room 1, the call-signal will not be heard because the television set is turned off, hence also the speakers 5.
Even if the video conferencing equipment 2 is not set to auto-answer, there are ways to connect a call unnoticed. As already mentioned, employees may be interested in information being discussed in a meeting room 1, either for the employees own benefits or spying for a competitor. Employees usually have access to the meeting rooms 1 and the equipment within them. By setting up a conference call and switching off the display unit 9 before a meeting starts, the remote party can listen in on the meeting unnoticed, as discussed above.
In modern office buildings, meeting room walls 3 are often made of glass or other transparent or semi-transparent materials, thru which infrared radiation may be transmitted. Employees or persons with access to the building (visitors, craftsmen etc.) could therefore answer or initiate a call from outside the meeting room by using a remote control 8.